This command make some action. But if the controlled device doesn't confirm the command receiving by some response, driver will wait for this response about 5 seconds. In this 5 seconds you can not send any other commands to the device.The driver is not waiting for 5 seconds becauseit is getting something back from the device.

The problem is that the HTTP driver waits for data anyway, the variant without data after the request was not provided.

You can use TCP driver instead of HTTP to send commands, it is not waiting for ~5 seconds.